Automatic and semiautomatic telephone system



April 26, 1927. R. MORDIN AUTOMATIC AND SEMIAUTOMATIC TELEPHONE SYSTEM 7 Filed Dec. 5, 1923 ts-Sheet I a v 4 1,626,206 Apnl 1927' R. MORDIN AUTOMATIC AND SEMIAUTOMATIC TELEPHONE SYSTEM Filed Dec. 1923 5 Shegfis-Sheet 2 April 26 1927.

1,626,206 R. MORDIN AUTOMATIC AND SEMIAUTOMATIC TELEPHONE SYSTEM 5 Shee Filed Dec. 5, 1923 j'i werzt'v 12 M p 26 1927' R. MORDIN AUTOMATIC AND SEMIAUTOMATIC TELEPHONE SYSTEM Filed Dec. 1923 5 Sheets-Sheet 5 Patented Apr. 26, 1927.

UNITED STATS RALPH MORDIN,

PATENT ()FFICE.

OF LONDON, ENGLAND, ASSIGNOB TO TEE RELAY AUTOMATIC TELE- PHONE COM'PANY, LIMITED, OF LONDON, ENGLAND.

AUTOMATIC AND SEMIAUTOMATIC TELEPHONE SYSTEM Application filed December 3, 1923,

My invention relates to inulti-exchange systems of automatic or semi-auton'iat-ic telephony.

It is particularly applicable to systems in which connections are set up over switching apparatus which is under the control, during its switching process. of transitorily used selecting apparatus though some of its "features have more general applicability.

My invention will be described, for purposes of illustration, in connection with one particular well known system of relay automatic telephone though it is to be understood that it is not to be limited thereto, except to the extent that such limitations may be embodied in the claims.

hen connections have to be set up between subscribers in a sub-exchange it is desirable that thisbe done without tying up junctions to a distant exchange and it is the object of my invention to provide a new and improved arrangement for accomplishing this.

According to my invent-ion I provide connecting apparatus which can be used under the control of a calling line to eiiect a connection to a line of av group of lines but which when first taken into use will connect the calling line to a line leading to a second connecting apparatus which is, also under the control of the calling line, adapted to cfi ecta connection to or towards a line of a different group oi lines the first connecting apparatus being out of control of the calling line unless apparatus associated with the line leading to the second connecting apparatus be controlled in a particular way.

I provide, further. in the first connecting apparatus, means whereby it the said first connecting apparatus is to be prepared for connecting to a line of the first group of lines the line leading to the second connecting apparatus shall be released.

A system somewhat similar to that described above is known in which a line upon becoming a calling line is connected to a connecting apparatus and this connecting apparatus is connected by a line switch to a line leading to second connecting apparatus. It is undesirable to have to provide :For each first connecting apparatus a line Serial No. 678,234, and in Great Britain January 5, 1923.

switch. This system has a further disadvantage that it is the inability of the second connecting apparatus to complete a circuit which puts the first connecting apparatus under controlot' the calling line.

Another system which is somewhat similar is known in which a subscribers line is connected by a secondary line switch to a connecting apparatus and in which an impulse responding apparatus with the secondary line switch. Both the connecting. apparatus and the impulse responding apparatus are operated'by some of the impulses representing the wanted number. For local connections the impulse responding apparatus may cause the secondary line switch to release the line leading to the connecting apparatus in order that the said line switch may pick up a line leading to a local connecting apparatus identified by the impulse responder or the impulse responder may cause the release of the line leading to the connecting apparatus and may itself connect the calling line to an appropriate local connecting apparatus.

Any system, however, in which the first connecting apparatus is under directive control of the calling line before apparatus associated with the second connecting apparatus shall have been controlled in a particular way is excluded from our invention.

My invention will now be described with reference to the accompanying drawings of which Fi 1 shows the general trunking scheme;

The identity of the various figures with the apparatus shown in Figure 1 is as tollows Figure 2 shows a current feeding group.

ABF, at the local exchange (KK is the, join line between the two parts of this figure.)

Figures 3, 3 and 3 shows a first con necting stage. FSC, at the local exchange; NN is the join-line between 2 and 3; QQ. is the join-line between Figs. 3 and 8; UU is the join-line between Figs. 3 and 3*; ZZ is the join-line between Figs. 2 and 3 Figure a shows a repeater REP at the main exchange; VV is the join-line between Figs. 3 and 4.

Figure 5 shows a first stage main exchange is associated recorder l Rliil; YY is the join line between Figs. 4 and 5.

Figure 6 shows a first stage local exchange recorder FIR (or lvlll); XX is the joinline between Figs. 2 and 6 and li lV the join line between Figs. 6 and 3".

The local exchange in Figure 1 may be of any convenient capacity and as represented may be for ten thousand lines (four thousand shown) divided into thousand line groups SE, SE SE SE. The trunks leading into groups SE SE SE. are only indicated. The retangle marked SL represents subscribers lines whicln by means ot' apparatus or" any known sort. become when calling connected to ABF. ABF represent microphone current feeding bridges and control relays which, when taken into use by a calling line extend such calling line through relay switching apparatus FSC, over a junction OJ, to main exchange ME. The jun tions OJ terminate at the main exchange in impulse repeaters REP, and are adapted temporarily to take into use impulse responders (known as recorders) IBM to which they will be connected by means of recorder connectors RC. The connection of a subscribers line by way of ABF, FSC, OJ, REP and BC to a recorder IBM takes place immediately the subscriber removes his receiver. The subscriber then transmits impulses representing the number of the wanted line. The first one or two trains of impulses are received upon IBM and serve to determine whether the call is for a line accessible from ME or for a line accessible from the local exchange. In the former case IBM will control the extension of the connection in the required direction. In the latter case IBM will cause the transmission of an impulse to ABF whereby ABF causes the release of OJ and becomes temporarily as sociated with a recorder Fill at the local exchange. For a local call, the next train ot impulses will be received on Fill which will determine "for which oi the groups Si l the call is destined and will control FS in such a manner that ABF will be connected to one of the trunks T, say i assuming that the call is for a line in group SE 6' will become temporarily connected with a final recorder FER upon which the final trains of digits will be received and which will control the further extension of the connection to a line in group SL.

Calls from the main exchange to the local exchange will come in on incoming unetions Iii" with which a recorder IJR becomes temporarily associated. IJR receives a train 0t impulses to determine into which group SE to extend the connection. The connection will be completed in the same manner as is a local connection.

In connection with Figure 1 it should be understood that each line represents a number of lines and each ABF, etc. represents a ninnber of those apparatus.

It should, of course be understood that there would be a number of outgoing zrunks OT, Figure 3 and there may, indeed. be a number of groups of such trunks. Further there would be a number of groups oi junctions or trunks similar to Z Figure 3, depending upon the number of thousand line groups comprising the local exchange. It all these groups be situated at one oliice the trunks would extend to apparatus similar to that shown in Figure 3 whereai's it they were in separate oiliices the junctions would extend to apparatus similar to that shown in Figure 3.

It may be pointed out here that the only difi'erence between the apparatus shown in lligures 3 and 3 that that shown in Fig ure 3 leads over a two wire junction to a repeater (Fig. 4-) which is adapted to picl; up a recorder whereas that shown in Figure 3" is adapted, itself, to pick up a recorder.

I will now describe in detail with the aid of the circuit diagrams how the above outlined connection is effected.

It is the usual practice in large automatic telephone systems to have letters as well as figures printed on the dial in order that a big number may be more readily remembored. The letters usually represent the exchange selecting digits.

For the purpose of this exampl it will be assumed that the local exchange is represented by BX and that the line required is designated by the number 2&32 The letters may correspond to any digit and will be talzen to correspond to 2 and 9 respectively. Thus the actual number of impulses in each train will be 29 2 l32.

lVhen the calling subscriber litts his receiver to initiate a call, his line is extended in a well known manner to a current feedin; group ABF Fig. 2 and a circuit 2 is closed through relay I over the subscribers line to negative point a at the bottom break ontact of relay ICU. By the operation of I circuit 3 is closed through a retarded releasing),- guard relay G closes circuit 4 for relay GK which in turn closes circuit 5 from negative point 7) through relay BB which energizes.

GX at the same time closes circuit 6 from negative point 0 through relay MX which energizes. M31 closes circuits 7 and 8 putting battery on the outgoing trunk marking relay ()TM Fig. 3 and junction marking relay .llil Fig. 3 respectively.

.IM is energized because one of the junctions of group A is to be used.

OTM closes circuit 9 from earth point (7 through the outgoing link marking relay OliM The combined operation of OTM. OIJMI and Jhl Fig. 3 completes circuit 10 from ill) cuit.

earth point (Z to negative point efor relay GS-Twhich operatesandcloses a holdin circuit foritself and .circuit 11 for relay SS.

SS operatesand completes circuit 12 from negative point e to earth point (Z for outgoing junction inarlting'relay OJM. This energizes and closes a holding circuit over contact f and circuit 13 containing OJC and OIAC. These relays operate and connect the outgoing trunk OT over outgoing link OL to the selected outgoing junction OJl.

OJ'G and OLC also complete holding circuit 14 from negative point Fig. 2 through MX OLC, OLB. OJC and OJB.

MX QOLB and OJ B energize in this cir- MX' breaks circuit 6 causing 'MX to dc-energize and thus break circuits 7'and 8 so that OTMand JM deeenergize. The operation of OLB marks "the outgoing link as busy by openingcircuit 9an'd theoperation of OJB, marks the outgoing junction as busy by opening circuit 10. The release of OTM broke the circuit of OJ M. The release of OJ M breaks the circuit of GS which in turn causes SS to de-energize. Thus the only relays in the connecting apparatus now in an, operated condition are those which are held over circuit 14.

The calling subscribers line is thus eX- tended to the repeater in the main exchange.

To save confusion in reading the circuits in Figures 2 and 4 these two figures maybe placed side by side-without Figures 3 and 3 between;;turther, relays bearing the same reference lettersin Fig. 4: asv are borne by relays in Fig. 2 will be followed by the numeral t), thus I The connection of the A and B feed ,(ABF or Fig. 2) to the repeater (Figure I) will result in the completion of circuit from negative point 9. relay I (2) through the twowindings of IS in parallel andthrough the winding of I t).

I (4) closes circuit 16 in which Grv operates. This relay does not respond to the impulses which shall be repeated by I (2) to I l).

G (4) closes circuits 17 and 18 the former from negative point and the latter from earth point 71 In circuit 17 relay FIFig. 5 operates and in circuit 18 relay BB l) operates.

F1 in operating completes circuit 19 through RC and P Figure 5.

P, the recorder pre.paring-relay,'in operating puts battery upon the main battery wire. shown as a heavy broken line. ,All the BK relays otth-e impulsecounting train will energize in parallel over circuit 20 derived from this main negative wire.

P putting on negative to the main. battery teedphereinatter referred to as P negative,

alsocauses' l tSR andRSR to energize over circuit .3.

The manner in which a recorder such as pulses corresponding to B have been releases atter a slight delay. RS11 causes the release of RSI after a .t'urther delay. the-recorder but before it can bring about :that release the following operations I take place. JR being operated leaves earth-on the it wire of therecorder-and removesit have been released by the operation RS'R- .until circuit 33 WEIS'COIIIPlEtGCl).

"that shown :in' Figure 5 operates is so well known that a detailed description of the circuit operations is thought to be unnecessary. It is su'fiiclent to state that when 1mceived circuit-'28'fron1 P negative at DC will be completed to operate ST.

Impulses-t'or letter X are then received by therecorder. This results in THD" being operated in circuit 29'tro1n P ncgativeat DC I The operationof THD completes circuit 31 in which J R operates. Circuit 31 was completed by MC which when it operated put a short circuit onItSR whichre- The release of RSH controls the release of from the B wire.

.This condition :upsetsthe balance of IS (4;) so that that relay will now operate and close circuit 32 for I00 (4) to operate.

Therepeater has now to give :this same condition, that isearth onthe'A Wire and nothing on the B wire, to the current feeding group Fig. 2.

ICU (4-) in operating closes circuit33 from earth-point is Fig. 5 for S (4)which operates and in turn closes circuit Better RS (4). (Note the recorder should not 'RS (4) operates and closescircuit- 35 which places earth upon the A wire through RS (4).

RS 'in operating closes-holding circuit 34 for RS (4:) so that RS (4-) is now independent of S -(4) and I00 (4).

The condition isnow-that there-is earth on the A wire (Fig. 2) and nothing on the B wire because this latter wire is open at contact RSG of RS (4). I

Referring to Fig. 2, IS therein will now be unbalanced and consequently will energize over circuit 35. IS closes circuit 36 over which ICU energizes and breaks circuit otIS which (lo-energizes. 100 now holds over itsown contacts. S now-has a circuit 37 over which to operate and thus closes circuit 38 for RR which operates and holds over circuit 38 At the same time IGO broke circuit 5 of BB which released. The release of BB is timed so that RR has time to operate first.

As soon as HR energizes and BB de-energizes JR will operate over circuit 39. and complete a circuit over its contacts for JR which operates and holds over circuit 40.

lVhen JR operated it opened circuit 5 and RR and ICC released. RR breaks circuit 39 so that JR de-energizes.

ICO by re-establishing circuit 2 brings about the re-energization of I and by reestablishing circuit 5 the re-energization of BB and by breaking circuit 35 brings about the release of IS.

The calling subscribers line will now be connected to the local recorder in a manner to be explained.

JR energizing breaks holding circuit 1% so that all the connecting relays in this circuit will be released.

MX remains energized over circuit 6 so that MX cannot energize again.

A circuit 4-1 was completed by the energization of JR which may be traced from battery in the current feeding group Fig. 2 ever make contacts of GX to earth point Z in the recorder connector Fig. 6 through FT. The first stage (i. e. the thousands) recorder at the local exchange is prepared and taken into use in an exactly similar method to that already explained in connection with the recorder at the main exchange.

The calling subscriber now dials thousands digit two into this local recorder.

The recorder operates in the well. known manner and when set for digit 2 operates THM The operation of THM completes circuit 60 in which is Jl .4 Figure 3*.

Figure 3 is a trunk (such as t Figure 1) leading into the same thousand group as is the calling subscriber. Connection to it from the A and B feed (Figure 2) is effected in the same way as was connection to the junction (Figure 3 This, it is thought, is suiiiciently well understood to render unnecessary a redescription of the operations.

T/Vhen ISB operates in the holding circuit it completes circuit to pick up a final three digit recorder which, in response to the last three figures of the number, brings about a connection between t and the wanted line in a manner well known in the art.

It should here be stated that the repeater (Figure 4) at. the main exchange would be capable under certain circumstances oi extending a connection to a particular thousands group in that exchange over apparatus similar to that shown in Figures 3 and 3".

Lines in the main exchange would be represented by l5 and four figures. Thus if the alling subscriber on the local exchange had. instead of dialling BXQ-l-SQ. dialled B2132 the operations would have been as follows Referring to Figure 5, the dialling of B would have caused the operation of ST and the dialling of 2 would have brought about the operation of THD This would have completed circuit 50 which would extend to a relay similar to JML 3", but situated at the main exchange and controlling apparatus there. i

Further, the repeater at the main exchange would be capable under other circumstances of completing connections to local exchanges other than that in which the calling line is situated over apparatus similar to that shown in Figures 3 and 3 Lines in these other local exchanges would be represented by B followed by some letter other than X (say M) followed by say a tour figure number. Th us, it the calling subscriber on the local exchange had, instead of dialling BX2432, dialled BM2432 the operations would have been as follows Referring to Figure 5, the dialling of B would have caused the operation of ST and the dialling of M would have caused the op eration of, say, THD This would have completed a circuit similar to 50 but operating upon a relay similar to JM Fig. 3 situated at the main exchange and controlling apparatus there which gives access to a local exchange other than that represented by BX.

The main exchange may be one of several main exchanges in which each main exchange would be represented by a diiierent first letter. For instance a second main exchange may be represented by the letter BE-77 It has been shown above that the receipt by the main exchange recorder, of impulses for first letter B brought about the operation of ST. Now the receipt by that recorder, of impulses other than for B as a first letter, would bring about the operation of one of the relays MX say MX for first letter M. The recorder would then mark out on circuit 51 to apparatus similar to that shown in Figure 8 but situated at the main exchange. The recorder can have been set for M either by a subscriber on main exchange 13 or by a subscriber on a local exchange in group B.

The apparatus similar to that shown in Fig. 3 at exchange B would be the outgoing end of a junction leading to main exchange M at which exchange it would terminate in a repeater similar to that shown in Figure 4.

The repeater at exchange M would pick up a recorder similar to that shown in Figure 5 and since the call is destined for exchange M or for one of its local exchanges ST at exchange l1 must be operated. The operation of ST can be etlec'ted in any well known manner. as, for instance, by the dialling of an additional impulse.

What I claim is 1. An automatic telephone system in which lines are selected by calling an invariable numerical designation comprising a main exchange. a number of lines thereon, a local exchange, a number of lines on the local exchange, a two-wire only junction be tween the exchanges, apparatus at the local exchange which upon any line thereon be coming a calling line will operate at once to extend this line to the junction, and means located in the main exchange and adapted upon being controlled by the calling subscriber in afiparticular manner so to modify the conditions of the said apparatus as to cause said apparatus to release the junction.

2. An automatic telephone system comprising a main exchange, a local exchange, two-wire only junctions connecting the exchanges, apparatus in the local exchange adapted to connect any calling line in the local exchange to an idle one of said junctions and means associated with the main exchange end of the selected junction for sending back an impulse to said apparatus should the call be a local one, so that said apparatus will release the junction.

3. A telephone system in which lines are selected by calling an invariable numerical designation comprising a local exchange a main exchange, a two-wire only junction from the local exchange to the main exchange, a number of lines on the local exchange, a number of lines on the main exchange, apparatus at the local exchange for connecting a calling line of the local exchange to the junction to the main exchange, means at the main exchange adapted to bring about under the control of the calling subscriber the connection of the junction to a wanted line in the main exchange or to permit the release of the junction, and apparatus at the local exchange adapted on the junction being thus released to be controlled by the calling subscriber to bring about connection of his line to another line on the local exchange.

4. A telephone system comprising two local exchanges, a main exchange and a junction from each local exchange to the main exchange, a number of lines on each local exchange of which some are junctions to the other local exchange, a number of lines on the main exchange, apparatus at each of the local exchanges for connecting a calling line of that local exchange to the junction to the main exchange, apparatus at the main exchange adapted to bring about under the control of the local subscriber the connection of the junction to any line in the main exchange or to permit the release of the junction to the main exchange and apparatus at each local exchange adapted on such release of the junction to be controlled by the local subscriber and to bring about connection of the calling line to another line on the same local exchange whether such line be the line of a subscriber on the same local exchange as the caller or a junction to the other local exchange.

5. A telephone system comprising a main exchange, a number of lines thereon, a local exchange, a number of lines thereon, twowire junctions connecting the exchanges, current feeding apparatus and switching apparatus at the local exchange adapted on one of the lines on the local exchange becoming a calling line to connect that line to an idlejunction, impulse repeaters located at the main exchange and associated with the junctions, an impulse responder adapted to be actuated by the repeaters and to extend the call to a line on the main exchange or to transmit an impulse back to the feeding and switching apparatus at the local exchange, whereby such apparatus releases the junction and an impulse responder at the local exchange adapted on the release of the junction to extend the calling line to one of the lines on the local exchange.

6. A telephone system comprising two local exchanges, a main exchange and a junction from each local exchange to the main exchange, a number of lines on each local exchange of which some are junctions to the other local exchange, a number of lines on the main exchange, current feeding apparatus and switching apparatus at each local exchange adapted on one of the lines of a local exchange becoming a calling line to connect that lineto an idle junction to the main exchange, impulse repeaters located at the main exchange and associated with the junctions connecting the local exchanges to the main exchange, an impulse responder adapted to be actuated by the repeaters and to extend the call to a line on the main exchange or to transmit an impulse back to the feeding and switching apparatus at the local exchange, whereby such apparatus releases the junction and an impulse responder at the local exchange adapted on the release of the unction to extend the calling line to one of the lines of the same local exchange or over a junction to the other local exchange.

In testimony that I claim the foregoing as my invention I have signed my name this 28th day of September, 1923.

RALPH MORDIN. 

